Oil burner system

ABSTRACT

An oil burner system for a furnace comprises a plural-speed electrical motor, a fuel pump, an air blower driven by the motor, an air conduit leading from the air blower to the oil burner, a plurality of oil conduits leading from the fuel pump to fuel nozzles in the oil burner, a solenoid-actuated valve in each of the oil conduits, a temperature and/or pressure sensor for sensing the temperature in the furnace, and a relay controlled by the temperature sensor for reducing or increasing the speed of the motor and for closing or opening one of the valves, thereby to reduce or increase the quantity of air fuel supplied to the burner.

[ 1 May 8, 1973 Primary Examiner-Ciarroll B. Dority, Jr. Attorney-Benjamin .l. Barish [54] OIL BURNER SYSTEM [76] Inventors: Kurt Lipper; Uri Chaim Lipper,

ABSTRACT both of l Reuben Street, Jerusalem,

Israel An oil burner system for a furnace comprises a pluralspeed electrical motor, a fuel pump, an air blower Filed:

[ pp NOJ 209,907 driven by the motor, an air conduit leading from the air blower to the oil burner, a plurality of oil conduits leading from the fuel pump to fuel nozzles in the oil Foreign Application Priority Data burner, a solenoid-actuated valve in each of the oil Jan.7, i971 Israel...........H..........................3596l conduits, a temperature and/or pressure sensor for sensing the temperature in the furnace, and a relay controlled by the temperature sensor for reducing or 3 increasing the speed of the motor and for closing or F opening one of the valves, thereby to reduce or in- 4 60 crease the quantity of air fuel supplied to the burner.

[58] Field of Search......................

7 Claims, 1 Drawing Figure [56] References Cited UNITED STATES PATENTS 2,5l6,062 7/1950 Logan...... .........................431/60 4 Z Starim Contral PATENTEU W 81973 44 Sim-ting OIL BURNER SYSTEM BACKGROUND OF THE INVENTION The present invention relates to oil burner control systems, particularly as used in domestic and industrial oil burner installations.

In the conventional oil burner installations, the amount of heat produced by the burner is usually controlled by adjusting air dampers provided in the installation which are operated by mechanical or hydraulic means or by a separate electrical motor provided for this purpose. The provision of air dampers not only increases the cost of the installation but also the dampers require frequent adjustment and maintenance.

An object of the present invention is to provide an oil burner system which does not use air dampers and therefore avoids the disadvantages mentioned above. Another object of the invention is to provide an oil burner system which is highly efficient and less expensive than the conventional system utilizing air dampers.

BRIEF SUMMARY OF THE INVENTION According to the invention, there is provided an oil burner system comprising a plural-speed electrical motor, a fuel pump driven by the motor, and an air blower driven by the motor. The air blower includes an air conduit to the oil burner, and the fuel pump includes a plurality of oil conduits to the oil burner, each of which latter conduits includes a solenoid-actuated valve. A temperature and/or pressure sensor senses the ,tem-

, perature and/or pressure in thefurnace, and, when it exceeds a predetermined one, controls .means for reducing the speed of the motor and for closing one of the valves. In this manner, the quantity of air and fuel supplied to the burner is directly controlled without the use of air dampers.

In the described embodiment, the control means comprises a relay having electrical contacts in the circuit to the plural speed electric motor and also in the circuit to .the solenoid-actuated valves. The energizing circuit of the relay is controlled by electrical contacts actuated by the temperature sensor.

In the preferred embodiment described, the motor has two speeds, two solenoid-actuated valves and two oil conduits, all controlled by the relay. It will be appreciated, however, the system could include a motor having more than two speeds, more than two valves and/or more than two oil conduits, controlled by the relay or other means controlled by the temperature sensor.

DESCRIPTION OF THE PREFERRED EMBODIMENT The invention is herein described, somewhat diagrammatically and by way of example only, with reference to the accompanying drawing illustrating an oil burner system constructed in accordance with the invention.

The oil burner system illustrated in the drawing comprises an oil burner 2 installed in a furnace 4. In this case, the oil burner comprises a pair of fuel nozzles 6,8 each supplied with fuel via a fuel conduit 10,12. Burner 2 further includes an air nozzle 14 surrounding the fuel nozzles 6,8, and supplied from air conduit 16. It is contemplated there could be a separate air nozzle 14 for each of the fuel nozzles, and also that there could be a single fuel nozzle supplied from the two fuel conduits 10,12.

The fuel is supplied from a fuel pump 20 driven by a motor 22, and the air is supplied by an air blower 24 driven by the same motor 22. Both the fuel pump 20 and the air blower 24 are mechanically coupled to the motor drive shaft 26 as shown schematically by the broken lines 26, 28 30.

Motor 22 is a plural-speed motor, being shown in the drawing as a two-speed motor having a first winding 32, which, when energized, drives the motor at low speed, and a second winding 34 which, when energized with winding 32, drives the motor at high speed. The speed of motor 22 is controlled by a relay RL having three sets of contacts, namely contacts RL-l, RL-2 and RL3. In the non-energized condition of relay RL (which is the condition illustrated in the drawing), contacts RL-l and R1-2 connect both of the motor windings 32,34 to the power supply 36, and therefore the motor32 is driven at high speed. In the energized condition of the relay, contacts, RL-l and RL-2 are actuated whereby they engage the upper contacts illustrated in the drawings so that only winding 32 is connected to the power supply 36, whereby the motor is driven at low speed.

A valve V1, V2 is included in each of the conduits 10,12 supplying fuel from the fuel pump 20 to the two nozzles 6,8. Each valve V1, V2 is actuated by a solenoid S1, S2. The third set of contacts RL3 of relay RL is in the energization circuit of solenoid S2, so that when the relay is energized, as shown in the drawing, contacts RL3 are closed, whereby solenoid S2 is energized and its respective valve V2 is opened. Upon the de-en'ergization of relay RL, however, its contacts RL3 are opened, thereby de-energizing solenoid S2 and closing its valve V2.

If desired, the energization circuit to solenoids S1 and S2 may also include a manual switch, SW1, SW2, to permit the manual control of these solenoids and their respective valves V1, V2.

A main switch SW3 is provided in the line to the power supply 36.

In addition, another switch SW4 may be provided to manually control the speed of motor 22. Manual switch SW4 includes two sets of contacts, SW4a and SW4b, bypassing the relay contacts RL-l and R1-2. Each of the contacts SW4a, SW4b includes three positions, namely; a middle nonoperating position; an upper position connecting the low speed winding 32 to the power supply; and a lower position connecting both windings 32 and 34 to the power supply for driving the motor at high speed.

The furnace 4 includes a thermostat TS for sensing the temperature within the furnace, the thermostat controlling a switch TS1 in the energization circuit to relay RL. If desired, the furnace may also include a pressurestat PS for sensing the pressure within the furnace, the pressurestat controlling another switch PS-l in the energization circuit of relay RL.

The burner includes an electrical igniter 40 controlled by an ignition system 42 of any conventional type.

The burner further includes a starting control 44 of known construction which, upon starting the furnace by depression of switch SW3, closes switch SW5 in the energization circuit of relay RL causing same to move its contacts from the shown non-actuated position to their actuated position. The motor 22 is thus driven at using a pt-Pt 13% Rh and chromel alumel thermocouples.

The results of the measurements are summarized in the following table:

Temperature C02 com. 02 cone. CO m.

Flamc, Stack, Flanw, Stack, Flame, Stack, Flame, Slack, Burner performance percent pcrccnt percent pcrccnt percent percent pcrccnt pci'cvnt Stage I. 5.8 gJhr 1130 108 10. 2 8.5 2.1 8. 3 0. 6 0 Stagcll,13.8 g./hr 1210 170 11. 11.1 2. 8 2. 2 1.1 0

low speed, which thereby vents the furnace, and valve V2 (as well as V1) is closed. At the same time, starting control 44 actuacts the ignition circuit 42 to energize the igniter 40. After a predetermined time delay (e.g. 30 seconds), starting control 44 closes switch SW6 in the energization circuit of solenoid S1, whereupon valve Vl opens, so that fuel is now fed through conduit 12 to its nozzle 6 causing ignition. Motor 22 is now operating at low speed, and the fuel is only flowing through valve V1. After another predetermined time delay (e.g. another seconds), starting control 44 opens switch SW5, de-energizing relay RI... The contacts of the relay thus return to the position shown in the drawing, wherein motor 22 is driven at high speed and both solenoids S1, S2 are energized, so that fuel flows through both valves V1, V2. The burner thus receives a large quantity of fuel, and also of air from air-blower 24.

When either thermostat TS or pressurestat PS senses a predetermined maximum temperature or pressure, its respective switch TS-l, PS-l is closed thereby re-energizing relay R1... Relay contact RL-l and RL-2 now connect the motor to be driven at low speed; and contacts RL-3 de-energize solenoid S2 and open its respective valve V2. Fuel is now supplied only to nozzle 6, and the supply of fuel and air to the burner is automatically reduced.

At a predetermined low temperature or pressure within the furnace, as sensed by thermostat TS, or pressurestat PS, its respective switch TS-l, PS-l is opened thereby de-energizing relay RL and increasing the supply of fuel and air to the burner in the manner described above.

When operating the system non-automatically, switch SW4 provides for manual control of the motor 22, and switches SW1, SW2 provide for manual control of the solenoid-valves VL, V2, as described above.

A burner constructed in accordance with the invention was used for heating of steam boilers. It used kerosene as fuel which was injected at a pressure of 125 psi into the combustion chamber. Primary air was supplied by a blower which could be operated at 1400 RPM or at 2800 RPM. At 1400 RPM (designated as stage 1) 5.8 gallons per hour of fuel were burned. The maximum quantity of air which could be supplied at- 1400 RPM of the blower was 800 m lhr at a pressure head of 20 mm of water. At 2800 RPM of the air blower (stage I1) the burner used 13.8 gallons per hour. The maximum quantity of air supplied by the blower at 2800 RPM was equal to l 100 m /hr at a pressure head of 40 mm of water.

Concentrations of CO, 0 and CO, were measured in the stack and in the flame region. The analysis was made with the aid of an Orsat analyzer. Temperature measurements were taken in the stack and the flame The efficiency of the burner was 85 percent in stage I and 87 percent in stage 11. This is considered to be a high burning efficiency as compared to the efficiencies customarily obtained in such burners. In this test, the excess air supplied was percent in stage I and 31 percent in stage II, and it is expected that a further increase of the efficiency could be achieved by decreasing the primary air supply by 5-10 percent.

Many variations, modifications, and other applications of the illustrated embodiment will be apparent.

What is claimed is:

1. Oil burner apparatus for a furnace comprising, a plural-speed electrical motor, a fuel pump driven by said motor, an air blower driven by said motor, an oil burner, an air conduit leading from said air blower to said oil burner, a plurality of oil conduits from said fuel pump to said oil burner, a solenoid-actuated valve in each of said oil conduits controlling the oil flow therethrough to said burner, a condition sensor for detecting condition in the furnace, and control means controlled by said condition sensor, when the condition in the furnace exceeds a predetermined maximum, for reducing the speed of the motor and for closing one of said valves, thereby to reduce the quantity of air and fuel supplied to the burner.

2. A system as defined in claim 1, wherein said control mean comprises a relay having electrical contacts in the circuit of the motor windings and also in the circuit of at least one of said solenoid-actuated valves, said condition sensor actuating electrical contacts in the energizing circuit of said relay.

3. A system as defined in claim 2, wherein said motor has two speeds, two solenoids-actuated valves, and two oil conduits, all controlled by said relay.

4. A system as defined in claim 3, wherein said oil burner includes two nozzles one supplied by each of said oil conduits.

5. A system as defined in claim 1, wherein said condition sensor is a pressure sensor for detecting the pressure in the furnace, said control means also being controlled by said pressure sensor.

6. A system as defined in claim 2, wherein said oil burner includes an electrical igniter, and wherein said system further includes starting control means which, upon starting the furnace: energizes said relay to cause the motor to run at low speed and also energizes the electrical ignitor; after a predetermined time delay opens one of said valves to cause a reduced amount of fuel to be fed to the burner; and after another predetermined time delay de-energizes said relay to cause the motor to run at high speed and fuel to be fed through both said valves to the burner; the condition sensor thereafter controlling said relay whenever the condition exceeds a predetermine maximum.

7. A system as defined in claim 2, wherein said condition sensor is a temperature sensor.

' m I: 4: nt 

1. Oil burner apparatus for a furnace comprising, a plural-speed electrical motor, a fuel pump driven by said motor, an air blower driven by said motor, an oil burner, an air conduit leading from said air blower to said oil burner, a plurality of oil conduits from said fuel pump to said oil burner, a solenoid-actuated valve in each of said oil conduits controlling the oil flow therethrough to said burner, a condition sensor for detecting condition in the furnace, and control means controlled by said condition sensor, when the condition in the furnace exceeds a predetermined maximum, for reducing the speed of the motor and for closing one of said valves, thereby to reduce the Quantity of air and fuel supplied to the burner.
 2. A system as defined in claim 1, wherein said control mean comprises a relay having electrical contacts in the circuit of the motor windings and also in the circuit of at least one of said solenoid-actuated valves, said condition sensor actuating electrical contacts in the energizing circuit of said relay.
 3. A system as defined in claim 2, wherein said motor has two speeds, two solenoids-actuated valves, and two oil conduits, all controlled by said relay.
 4. A system as defined in claim 3, wherein said oil burner includes two nozzles one supplied by each of said oil conduits.
 5. A system as defined in claim 1, wherein said condition sensor is a pressure sensor for detecting the pressure in the furnace, said control means also being controlled by said pressure sensor.
 6. A system as defined in claim 2, wherein said oil burner includes an electrical igniter, and wherein said system further includes starting control means which, upon starting the furnace: energizes said relay to cause the motor to run at low speed and also energizes the electrical ignitor; after a predetermined time delay opens one of said valves to cause a reduced amount of fuel to be fed to the burner; and after another predetermined time delay de-energizes said relay to cause the motor to run at high speed and fuel to be fed through both said valves to the burner; the condition sensor thereafter controlling said relay whenever the condition exceeds a predetermine maximum.
 7. A system as defined in claim 2, wherein said condition sensor is a temperature sensor. 